Pseudolite interference mitigation and signal enhancements using an antenna array

Several terrestrial communication systems use the same frequency spectrum as Global Navigation Satellite Systems (GNSS) or bands close to it. Pseudolites constitute one such system that generally uses the GNSS spectrum for signal propagation. The signals from pseudolites in the operating region play a crucial role in augmenting satellite based user navigation. These signal transmitters are deployed at ground stations for the majority of their applications. In the near region, pseudolites are overpowered and cause impediments to normal receiver operation due to an increase in the noise floor. Interference and jammers form another source of GNSS disruption. Interference could result from intentional jammers or unintentional signal disturbances from in-band or out-of-band high power sources. A GNSS user can experience interference from near region pseudolites as well as from other interferers. These interference sources may have directional coexistence with pseudolites or GNSS satellites. Such disruptions might completely block signal acquisition and lead to processing failure. The capability of antenna array space-time processing to counter the above mentioned scenario is demonstrated herein. In addition to interference mitigation, pseudolite signal recovery in the near region and subsequent enhancements are shown. Results that demonstrate improvement in measurement geometry for various antenna array configurations and different processing modes are also shown.